Make compilation of tor_memdup_nulterm() with dmalloc

Fixes bug 11605; bugfix on 0.2.4.10-alpha.
Search for python by looking for "python2.7" and "python3.3" as well.
Changes file for bug 11632.
Stop leaking memory in error cases of md parsing

When clearing a list of tokens, it's important to do token_clear()
on them first, or else any keys they contain will leak.  This didn't
leak memory on any of the successful microdescriptor parsing paths,
but it does leak on some failing paths when the failure happens
during tokenization.

Fixes bug 11618; bugfix on 0.2.2.6-alpha.
Merge remote-tracking branch 'origin/maint-0.2.3' into maint-0.2.4
Merge remote-tracking branch 'origin/maint-0.2.4'
Add contrib/tor.service for use with systemd
Put tor.service in the right place, and autoconfify it

This closes 8368.
Quench gcc's complaints about discarding constness in TO_ORIGIN_CIRCUIT.

This was previously satisfied by using a temporary variable, but there
are three other instances in circuitlist.c that gcc is now bothered by,
so now introduce a CONST_TO_ORIGIN_CIRCUIT that takes a const
circuit_t instead.
changes file for last patch
Merge remote-tracking branch 'public/bug11605_024'
Drop the MaxMemInCellQueues lower limit down to 256 MB.

on #9686, gmorehose reports that the 500 MB lower limit is too high
for raspberry pi users.

This is a backport of 647248729fa65f0e51d062e2af8f4e8b38592bf5 to 0.2.4.

Note that in 0.2.4, the option is called MaxMemInCellQueues.
Merge remote-tracking branch 'origin/maint-0.2.4'

Doing an "ours" merge to avoid taking 35699ef9f5d2814203653e16c, which is
a cherry-picked backport of 9686.